Ticket #45389: 45389.patch

src/wp-includes/post.php

@@ -4546 +4546 @@
                 $excerpt = strip_tags( $postdata['post_excerpt'] ? $postdata['post_excerpt'] : $postdata['post_content'] );
 
                 if ( strlen( $excerpt ) > 255 ) {
-                        $excerpt = substr( $excerpt, 0, 252 ) . '…';
+                        $excerpt = mb_strcut( $excerpt, 0, 252 ) . '…';
                 }
 
                 $trackback_urls = explode( ',', $tb_list );